* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

html {
  height: 100%;
}

body {
  height: 100%;
  background: url(../pic/f1_1.jpg) no-repeat center 0 / cover;
}

.cloud img {
  position: absolute;
  left: 50%;
}

.cloud img:nth-child(1) {
  margin-left: -250px;
  top: 20px;
  animation: cloud 2s linear infinite alternate;
}

.cloud img:nth-child(2) {
  margin-left: 300px;
  top: 100px;
  animation: cloud 2s 1s linear infinite alternate;
}

.cloud img:nth-child(3) {
  margin-left: -550px;
  top: 200px;
  animation: cloud 2s 2s linear infinite alternate;
}

@keyframes cloud {
  100% {
    transform: translateX(60px);
  }
}

.text img {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  animation: expand 1s;
}

@keyframes expand {
  0% {
    transform: translate(-50%, -50%) scale(1);
  }

  20% {
    transform: translate(-50%, -50%) scale(0.1);
  }

  50% {
    transform: translate(-50%, -50%) scale(1.3);
  }

  70% {
    transform: translate(-50%, -50%) scale(0.2);
  }

  100% {
    transform: translate(-50%, -50%) scale(1);
  }
}